<template>
	<div>
		<router-link 
		   tag="div" 
		   to="/" 
		   class="header-abs"
		   v-show="showAbs"
		>
			<div class="iconfont header-abs-back">&#xe658;</div>
		</router-link>
		<div 
		   class="header-fixed" 
		   v-show="!showAbs"
		   :style="opacityStyle"
		>
			<router-link to="/">
            <div class="iconfont header-fixed-back">&#xe658;</div>
            </router-link>
			景点详情
		</div>
	</div>
</template>

<script>
export default {
	name: 'DetailHeader',
	data () {
		return {
			showAbs: true,
			opacityStyle: {
				opacity: 0
			}
		}
	},
	methods: {
		handleScroll () {
			const top = document.documentElement.scrollTop
			if (top > 60) {
				let opacity = top / 140
				opacity = opacity > 1 ? 1 : opacity
				this.opacityStyle = { opacity }
				this.showAbs = false
			} else {
				this.showAbs = true
			}
		}		
	},
	activated () {
		window.addEventListener('scroll', this.handleScroll)
	},
	deactivated () {
		window.removeEventListener('scroll', this.handleScroll)
	}
}
</script>

<style lang="stylus" scoped>
@import '~styles/varibles.styl'
.header-abs
  position: absolute
  left: .2rem
  top: .2rem
  width: .8rem
  height: .8rem
  line-height: .8rem
  border-radius: .4rem
  text-align: center
  background: rgba(0, 0, 0, .8)
  .header-abs-back
     color: #fff
     font-size: .4rem
.header-fixed
  z-index: 2
  position: fixed
  top: 0
  left: 0
  right: 0
  height: $headerHeight
  line-height: $headerHeight
  text-align: center
  color: #fff
  background: $bgColor
  font-size: .32rem
  .header-fixed-back
    position: absolute
    top: 0
    left: 0
    width: .64rem
    text-align: center
    font-size: .4rem
    color: #fff
</style>